SU1052540A1 - Method for continuously measuring gas permeability of charge in blast furnace - Google Patents

Abstract

THE METHOD OF CONTINUOUS MEASUREMENT .f REN | 1TH OF GAS PERMEABILITY OF THE ROSHTY IN THE DOMAIN FURNACE, including the measurement of differential pressure drops of gas at the bottom of the charge column at stable flow rates, pressure of flue gas, level of charge, tl and h and h and so that, in order to predict the content of fines in the ore part of the charge, the gas pressure drop over the column section from the level of the gaps equal to 0.05-0.07 of the entire column height is additionally determined, at ecs, a change in the differential by + 10% corresponds to fraction content -. 5 mm in the ore part of the mixture by ± 1.5%.

Description

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fi. 1 21 22 2U The invention relates to metallurgical industry, in particular to the domain production. The closest to the present invention is a method for continuous measurement of the gas permeability of a mix in a blast furnace, including measurement of differential pressure drops of gas over the height of the charge column at steady flow rates, top gas pressure, charge level of charge 11. A disadvantage of the known method is the lack of gas permeability control of the charge portion entering the furnace, from which the gas permeability of the charge column is formed. Only the gas permeability of the already formed charge column with a height of 1 / 3-1 / 4 of the furnace height is measured. The permeability of the charge column of such a height is no longer possible to change by changing the current loading parameters, to blow. Therefore, an increase in private pressure drops above optimal values usually leads to a forced decrease in the intensity of the kiln operation. The purpose of the invention is to predict the content of fines in the ore portion of the charge. This goal is achieved by the fact that according to the method of continuous measurement of the gas permeability of the charge in a blast furnace, including the measurement of the differential pressure of the gas over the height of the charge column at stable flow rates, blast furnace pressure and charge level, further defined. The differential pressure of the gas in the section of the column from the level of the embankment equal to 0.05-0.07 of the entire height of the charge column, while a change in differential of ± 10% corresponds to a change in the fraction content of 5 mm in the ore part of the charge by + 1.5% . It is known that the angle of inclination of the embankment surface to the horizon fluctuates within 17-2 (L The radius of modern blast furnaces fluctuates within 3.3-4 m. Then the height of the funnel funnel after lowering the feed will be within fi 1i tq; -ot (3, 3-4) t {17 + 20) - 1.45-1.07 m. The height of the layer from one portion (hearth) is usually 0.5-0.7 m. In order to obtain a stable differential value, The pressure take-off hole must be below the funnel level before the next batch is loaded. Between the feeds, the embankment level is lowered to the height of one layer, the portion charge, i.e. by 0.5–0.7 m. Gas permeability is disturbed by fines fluctuations in the charge. Moreover, all fluctuations in the content of fines can be fully attributed to the ore part of the charge. Coke is loaded sorted and contains almost nothing at the moment of loading. As experiments show, coke is located in the furnace in separate layers and does not limit the gas dynamics of the process. The permeability of the charge to be charged varies depending on the content of fines in the ore part of the charge and on the ore load. The table presents the results of changes in the granulometric composition of the main ore material of the agglomerate under production conditions (data obtained at different times and represent extreme values of% 7 the average weighted particle size of the first agglomerate, determined by the known method of calculation with fines less than .5 mm, is 14 , 9 mm, with the exception of small things equal to 18.8 mm. For the second agglomerate, the corresponding average sizes are 15.6 mm and 17.3 NM. The octapi have a more stable particle size, which varies in a narrow interval of 20-8 mm, from the average is also 16–15 mm. Thus, the average particle size of the base iron ore material in the mixture is 15–18 mm. Therefore, the gas permeability of the charge under the influence of Fines fluctuations (fraction less than 5 mm) is estimated with respect to this size at constant coke, loading system and other quantities. The connection between the average size of the base material and the fines is that the content of fines in the mixture has a different effect on the gas permeability of the layer depending on the ratio of the average size of the base material to Independent user the size of fines particles. As shown by experimental data, with a ratio of average particle sizes of materials and fines c / s.2, 2. an increase in fines content by 10% causes an increase in pressure drop - (or decrease in gas permeability) by 20%, while an increase in fines content by every 10% increases re; pressure drop by 70-80%. Since for a blast furnace charge, a fraction of less than 5 mm is considered a trifle, i.e. its average size is 2.5 mm, then the ratio is df- .. / d. with respect to the blast furnace, ranges from 5-7.0. Thus, the change in pressure drop by ilO% under the conditions of the blast furnace corresponds to the fluctuation of the fines content in the ore part of the charge by ± 1.5%. The obtained conclusion is confirmed by the results of sintering sieves obtained during the measurement of differential pressure drop in the area under the mound - head of the charge column 2m high. FIG. Figure 1 shows a diagram of the differential pressure drop of a gas in the area below the level of the top of the mill, starting from 24 hours on April 21 to 7 hours on April 22; in fig. 2 is a diagram for the period end - from 15 to 22 on April 22, in FIG. 3 - the diag ram of the upper pressure drop of the gas in the section of the charge column in the middle of the mines - top furnace from 24 hours April 21 to 23 hours 22 April. Example 1. B. Basic agglomerate the fines content is in the range of 10-12%. At the same time, the differential pressure drop of the gas in the section with a height of 2 m 0, 09-0.1 atm (as shown in the diagram in Fig. 1 during periods of 0-1 h 30 min and 3-4 h) ,. The content of fines less than 5 mm in it is determined by the sintering of the skip agglomerate, which is distributed in time as follows: Time, h Content of fines,% 012.6 110.2 217.5. 35.88 410.5 516.8 With a change in the fines content in the agglomerate, the gas pressure drop changes synchronously from 0.09 to 0.16 atm. to 17.5% (i.e., 7.5%), the pressure drop increases by 60%, i.e. for every 10% fines, the pressure drop increases by 80%. High gas pressure drop, which arose with an increase in the content of fines, can be reduced by replacing in separate feeds the usual skip coke of the 80–40 mm fraction with the smaller coke of the 40–25 mm fraction and using the KRKR loading system. When using this method, the pressure drop is reduced by 30-45%. Example 2. A mixture consisting of a mixture of coke fraction 80–40 mm and production sinter at ore load 3 is loaded into a cylinder 300 mm in diameter. At this, the ratio of average sizes of coke particles to the average particle size of the agglomerate. is 7. The purge fraction, mm I + 40 G 4

Small agglomerate2, 0

Large sinter 5, 2

24.1

34.6

34.9 11.7 36.4 34.9 layer with a height of 0.5 m with air at a speed of its movement (on the empty section of the cylinder) 1.08 m / s. The differential pressure is measured, the value of which is 338 mm aq / st / m. After this, the same agglomerate is mixed with a coke of a fraction of 40–25 mm under the same ore load 3 and loaded into a cylinder. The ratio of average particle diameters of coke and agglomerate decreases to 2.3. Blow a layer of air at a speed of movement of 1.08 m / s on the empty section of the cylinder). In this case, the pressure drop decreases to 206,225 mm.W./St / m. As can be seen, with a decrease in the ratio of s / s to 2.3 and the use of a loading system that mixes coke with sinter, the gas permeability increases by 30.5-50%, which compensates for an increase in the content of fines in the sinter by 5-6%. When the content of fines in the agglomerate decreases by 5-6%, the gas pressure drop decreases by 30-50%. According to technical standards, a 1% reduction in the fines content in the charge leads to a reduction in coke consumption by 0.9%. In proportion to coke saving, the ore load increases (by 4-5%). An increase in the ore load by 4–5% according to the above method results in an increase in the pressure drop by 20–25%. As can be seen, the proposed method of measuring the differential pressure drop and the received effects allow maintaining a stable gas pressure drop, and, consequently, a smooth course of the furnace. The pressure drop in the charge column between the middle of the shaft and the top furnace has a wave-like character. Comparing the differential and upper (top-hole) pressure drops at the same time shows that the rise and lowering of the differential pressure in the charge column is detected 1.0-1.5 hours after the corresponding raising and lowering of the differential differential pressure, i.e. . with a delay of 1-1.5 hours from the time of loading. . The created resistance of the charge column cannot be changed and causes a corresponding decrease in furnace productivity. G 25-10 T 10-5

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Claims (1)

METHOD OF CONTINUOUS MEASUREMENT-1 OF RHENE GAS PERMEABILITY OF A BURNER IN A BLAST FURNACE, which includes measuring differential pressure differences. the gas at the outlet of the charge column with stable blast flow rates, blast furnace gas pressure, charge charge level, and the fact that, in order to predict the fines content in the ore part of the charge, the gas pressure difference in the section is additionally determined column from the level of mound, equal to 0.05-0.07 of the entire height of the column, while the change in the difference by + 10% corresponds to the change in the fraction fraction - 5 in the ore part of the charge by + 1.5%. 15 16 17 18 19 20 21 22 23 U „L052540>